This study investigated the effects of the 6 Minutes Journal, a commercial diary combining several positive psychology interventions, including gratitude, goal-setting, and self-affirmation exercises, on several mental health outcome measures. In a randomized controlled trial, university students were randomly assigned to one of two groups: 6MT and a wait list control group. Participants in the intervention group were instructed to follow the instructions of the 6MT for 4 weeks. Participants in both groups completed measures of perceived stress, positive and negative (...) affect, self-efficacy and resilience at baseline, after 2, and 4 weeks. We used path-analyses with autoregressive and cross-lagged effects to test our hypotheses of the effects of the 6MT. Participants in the intervention group reported decreased levels of perceived stress and negative affect, as well as increased levels of resilience and self-efficacy compared to the control group. Positive affect was not statistically significantly influenced. The data showed a statistically significant increased levels of self-efficacy and resilience only after 4 weeks, suggesting that changing these constructs needs more time. The 6-minute diary does not appear to make individuals fundamentally more positive. However, the intervention may have a protective function against negative influences on well-being. (shrink)